A disinfection arrangement for a hemodialysis machine is described in German Patent Specification No. 34 47 989. This hemodialysis machine is provided with an inner shunt conduit which, in principle, connects the machine's used dialysis solution outlet with the inlet of the machine or, more specifically, a mixing chamber for the dialysis solution. A disinfectant is thus supplied to the dialysis machine and is made to circulate in the closed circuit through the machine and through the aforementioned shunt conduit. The disadvantage with this disinfection arrangement is that the same solution circulates on the clean side as well as on the dirty side of the dialysis machine. By the terminology "dirty side" of the machine is meant the side which, during normal operation, is positioned downstream of the dialyzer and contains the dialysis solution which comes from the dialyzer, which can contain blood plasma (ultrafiltrate).
Another disinfection arrangement for a dialysis machine is described in European Patent Application No. 208,090. This machine is provided with a shunt conduit which extends from a dialyzer coupling (the clean side of the dialyzer) to the inlet of the dialysis machine. In this manner, a recirculation circuit is formed which only includes the clean side of the dialysis machine. Additionally, a heating element is positioned in a water vessel in the recirculation circuit. The heating element is used to successively heat up the fluid, normally water, which is circulating in the circuit, to a high temperature, for example above 95.degree. C. In this manner, a heated disinfection and/or sterilization is achieved. A small portion of the warm fluid is tapped off to the dirty side of the dialysis machine and passes therethrough, and out to the outlet, whereby the dirty side of the machine is also disinfected. The temperature of the fluid, however, falls during this passage, which results in the disinfection of the dirty side being less effective.